A police officer considering a motorcycle beat needs a strong desire to learn, must be unafraid of a motorcycle and possess some athletic ability. Police motorcycle operation is one of the most hazardous jobs in law enforcement today, and officers require advanced training, followed by periodic refresher training. Harley Davidson and the Northwestern University Traffic Institute jointly offer two sets of driving classes: an operator class and a training officer class. The operator course teaches both how to operate a motorcycle and how to do evasive actions. It also covers machine nomenclature and preventive maintenance, slow maneuvers, braking, curve negotiation, and defensive driving. Instructors also teach officers to plan for other people to do the most unexpected thing with the least amount of warning. These exercises teach officers how to ride in a state of readiness so they are prepared to take evasive action. Passing the operator class is a prerequisite for attending the training officer class.